Reproducer for radio receiving apparatus



1,636,940 y 1927' T. LINDENBERG REPRODUCER FOR RADIO RECEIVING APPARATUS Filed Jan. 1.3. 1926 QQD jyteorlore .Z inakneiy 6cm new 'lfatented July 26, 1927.

THEODORE LINDENBERG, OI COLUMBUS, OHIO.

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BECEIVING APPARATUS.

Application filed January 18, 1928. Serial No. 80,917.

The present invention is directed to an improved amplifier or reproducer for use' in connection with radio receiving apparatus. The object of the invention is the provision of a re roducer embodying peculiar features of esign by which the quality and volume of the emitted sounds are of a greatly improved character, as compared with the present ordinary apparatus for this pur ose, and wherein not only are thebasic or Fundamental sounds reproduced but, in; addition, the overtones and rich harmonic shadings are locall developed to enhance the tonal quality 0 the sound, to permit of a faithful rendition of the artists efforts in reproduced form and "to .increase correspondingly the enjoyment and pleasure of the listeners. M I

In accordance with theihventionthere is provided a radio reproducer consisting of a plurality of indivi ual reproducing units, and wherein the amplifying horns of said units have the resonant walls thereof formed from different materials possessing varying resonating properties, each of said units having the capacity of developing certain sounds to better advantage than other sounds, whereby said units operate to develop the received signal energy completely and elaborately providing a means, covering the entire range of audible sound wave frequency, for developing, for example, the characteristic sounds of various orchestral instruments, so that each individual sound may be reproduced in proper proportion to the entire volume of sound reproduced. It has been observed that a single radio repro ducer or loud speaker of ordinary design does not function to develop adequately to reproduce clearly and faithfully the sounds produced by the artist. It has been noted that in loud speakers, where the same are of the horn or cone t pe, there is present in the reproduced soun the characteristic, peculiar mechanical properties of the reproducer. Moreover, a reproducer having a diaphragm of fixed sides and an associated ampligying horn of determined area and forme from a single material can not function to accurately reproduce the noise and sounds of, for example, various orchestral instruments. A lar e reproducer of wood ma develop the strmgedinstruments of an orc estra satisfactorily but would not develop M metallic instruments. Realizing, therefore,

in a true phonetic way the brass or 11 the inherent limitations in reproducers of this kind, the presentuinvention consists in the grouping of a number of reproducer units, each having amplifying elements of varying size and material and adapted to operate simultaneously from a single radio recelvmg apparatus, the arrangement being such that throughthe use of a plurality of such elements the reproduced sound would be(properly developed throughout the entire au 1ble range of sound frequency, resulting in the production of sound possessing strengthand body with the overtones present in full degree, enabling the various individual sounds to beheard in their true relative proportions with the entire bod of sound, and overcoming especially the -t inness. and mechanical limitations of the ordinary radio reproducer.

For a further understanding of the inven tion reference is to be had to the following description and the accompanying drawmg in which:

Figure 1 is a frontelevation of a radio re-' producer constructed in accordance with the present invention, parts of the cabinet of said reproducer being ,shown in section to disclose the interior structure.

Flgure 2 is avertical cross-sectional view on the line 22 of Figure 1.

Figure 3' is a plan view disclosing the relative proportions of the diaphragms used in the several units of the reproducer.

Referring more particularly to the accompanying drawing the numeral 1 designates the improved reproducer comprising the present invention in its entirety. In the specific form of the invention illustrated and hereinafter described the reproducer is formed to include a cabinet 2 of any apropriate design, which is preferably ormed in a cabinet such as form that of the radio receiving apparatus (not shown) with which the reproducer is associated. The cabinet includes a base 3, vertical end walls 4, a back wall 5 and a top 6. Within the cabinet there is arranged a horizontally extending wall 7, that divides the interior'of a cabinet into an up'per'amplifying chamber 8 and, a lower ap aratus and battery chem -ber 9. The cham er 9 is closed by a front wall 10, while the amplifying chamber 8 is 7' preferably 0 en at i'ts front but may be partially closed y a foraminated wallor screen cabinet is a plurality of loud speaker or reproducer units 12. In thepresent 111'- stance these units have been shown as of the the fact that the area of the diaphra i smaller in area than the horn at the right,

and this is true, as shown in Figure 3, in regard to the relative proportions of the diaphragms13. The horns 14, may, for exam le, be formed from metal, the horns 14", rom a composition material, such as in such a manner that the sound wi wood fiber or the like, whereas the horn 14 may be formed from "grained wood or a combination of wood and metal. It will be seen that due to the varying size of materials from which the units 12 are formed each particular unit will be adapted toamplify to better advantage certain individual sounds than the remaining units, and by virtue of the assembly of these units in a sin le structure, the final sound produced will possess a leasing combination of both beauty and v0 ume not foundin analogous apparatus of which I am aware.

referably, the units 12 are arranged so that their outlets face toward a sounding board 15 mounted for vibration within the chamber 8 of the cabinet and which reflects the sound throu h the screened front wall of the cabinet. i will be observed that the sounding board is more in the nature of a reflector and is of considerable utilit in discharging the sound from the repr ucer 1 appear to emanate from the front of the reproducer rather than 'from a point deep in the interior thereof. 2

The chamber 9 of the cabinet includes in this instance an audio-amplifying unit 16, usually of the so called push-pull variet The batteries for this ap aratus may placed in the chamber 9, an leads 17 extend rom the output side of the am lifierto the reproducer units 12. Manna y operated switches 18 are preferably arranged in connection with these leads so" as to control at will the o ration of each unit, namely one or more 0 said units to be cut of! whenever desired. An inat connection 19 is arranged at the si e of the amplifying apparatus 16 and with which the leads from the associated receiving set are detachably connected. It will be appreciated that any standard form of radio receiver ma be utilized in connection with the repro ucer and that the latter will be enabled to augment the strength of the received signal energy to an "extent necessary to operate the reproducer units to their usual working power. The back of the cabinet is provide with a hinged wall 20 affording access to the interior of the chamber 9.

In view of the foregoing description, taken in connection with the accompanying drawing, it will be seen that the present invention provides a radio reproducer or loud speaker of unusual desi which possesses t e capability of repr ucing the electrically created sound oscillations to a degree veryclosely approximating the originally created sounds of the artist. There is present in the reproduced sound a vitality and body of natural strength and vigor, having a rounded and blended character wholly unusual, so far as I am aware, in apparatus of a similar nature. In forming the amplifiers of the reproducin units from different materials a very mar ed improvement in the emitted sound has been noticed, and this has been sup lemented by the varying size of the am 11 ying units. The device in its commercia form ma be placed in an attractively nodeled ca inet either in connection -witlfvor remote from an associated radio receiving set.

What is claimed is: g I 1. A reproducer for radio receiving apparatus comprising a plurality of reproducing units, said units being formed to include amplifying sections, one of said sections having the walls thereof formed from wood,

another section from metal and a third from a moulded composition material, and means permitting said units to be simultaneously energized.

2. In radio re reducing apparatus, a plurality of repro ucing units, each of said units being ormed to include an am lifying horn, the horns of said unit ing formed fromdifierent materials and of varying size and proportions, a signal amplifying unlt, and leads extending from said signal amplifying unit to said reproducing units for eifecting simultaneous operation of the latter.

3. A'structure as specified in claim 2 in connection with switches provided in said leads for controlling selectively the operation of said reproducer units.

In testimony whereof I aflix m signature.

" THEODORE LIND NBERG. 

